1. Field of the Invention
The present invention relates to a service-plug attaching structure and, more particularly, to an attaching structure capable of preventing a service-plug from exposure to water.
2. Description of the Related Art
Such vehicles as electric vehicles which employ an electric motor and hybrid vehicles which employ both of an engine and an electric motor run as electric power is supplied from an on-board power source device to the electric motor. Such vehicles have high-voltage circuits which operate on the power source device, and are equipped with a service-plug (circuit opening/closing device) for shutting off and again conducting circuit currents of the high-voltage circuits to secure safety of a worker who carries out inspection/maintenance or troubleshooting work (refer to JP-A-9-104239).
Incidentally, power source devices are large, heavy high-voltage battery units and are composed of a battery assembly which is a series connection of plural secondary batteries, a pair of end plates which hold the battery assembly between themselves, an electric junction box disposed between the battery assembly and the electric motor, and other components. Therefore, conventionally, a dedicated frame (battery frame) is formed under a vehicle floor panel (floor metal plate) and a space (battery space) to house the power source device is secured between the battery frame and the floor metal plate. The power source device is mounted on the battery frame and housed in the battery space.
The service-plug is connected to both of a vehicle control unit (motor control unit) provided in a space (motor room) which is separate from the battery space and a harness (high-voltage harness) that is connected to the electric junction box, and can thereby shut off and again allow flow of electricity to high-voltage circuits (e.g., a connection circuit between the motor control unit and the electric junction box) which operates on the power source device, at an intermediate potential. Therefore, to electrically connect the motor control unit and the power source device (electric junction box) via the service-plug, it is necessary to make the high-voltage harness lead out of the battery frame and make necessary wiring. Since the electric junction box is mounted, together with the battery assembly, on the battery frame which is formed under the floor metal plate, in making the high-voltage harness lead out of the battery frame and making necessary wiring, it is necessary to take a thorough waterproof measure so that the put-out portion of the high-voltage harness is not exposed to water.
JP-A-9-104239 discloses a service-plug attaching structure in which such a waterproof measure is taken. In this attaching structure, a high-voltage harness passes through a vehicle body panel (dash panel) that separates a motor room and a vehicle compartment. An attaching/detaching unit for attaching and detaching a service-plug which is connected to the high-voltage harness is provided. A floor metal plate is formed with an opening through which the attaching/detaching unit projects, whereby the attaching/detaching unit is exposed to the vehicle compartment. In this attaching structure, since the attaching/detaching unit is exposed to the vehicle compartment, it is not necessary to make the high-voltage harness lead to (expose it to) the outside of the vehicle (vehicle compartment). This makes it possible to attach and detach the service-plug from the vehicle compartment, and to thereby safely perform connection work for high-voltage circuits (e.g., a connection circuit between a motor control unit and an electric junction box) which operate on a power source device.
However, the service-plug attaching structure disclosed in JP-A-9-104239 is merely such that a measure for preventing a put-out portion of the high-voltage harness from being exposed to water is taken by not exposing the high-voltage harness to the outside of the vehicle (vehicle compartment) whereas exposing the attaching/detaching unit to the vehicle compartment. Therefore, this measure is insufficient because it includes no waterproof measure against an event that water leaks to the neighborhood of the service-plug due to a careless act of a driver or passenger such as pushing-down of a cooler in the vehicle compartment or opening of a window in the rain, that is, it includes no measure for protecting the service-plug (in other words, attaching/detaching unit) against water leakage or water entrance in or into the vehicle compartment. If the service-plug were pulled out in a state that water exists around it, serious trouble might occur such as short-circuiting of the battery assembly.